Caught in a violent storm, 852 passengers died within minutes after winds ripped off the bow door of the ferry Estonia in 1994, sending icy water gushing through the car deck.

On Friday, authorities sought clues after another "roll-on, roll-off" ferry sank in the Red Sea with nearly 1,500 people aboard. The cause was unknown, but experts said the vessel's design may have been a key factor.

The 35-year-old ferry Al-Salaam Boccaccio 98 had a similar — but older — door construction to the Estonia, said Johan Franson, safety expert at the Swedish Maritime Administration.

"The basic problem with these ships is that if water enters the car deck, it makes the ship unstable and it can then capsize," he said.

Outdated designs and safety measures can quickly turn older ships into death traps.

David Osler, of the London shipping paper Lloyds List, said "it would only take a bit of water to get on board this ship and it would all be over."

"The percentage of this type of ferry involved in this type of disaster is huge," Osler said.

But new designs — which could keep stricken vessels afloat for up to 24 hours — could soon be rolling off the production line.

Since the Estonia disaster in the Baltic Sea, Swedish and international experts have come up with safety improvements aimed at drastically decreasing the risk of flooding.

Researchers at the Chalmers University of Technology in Goteborg and SSPA Sweden, a company focusing on maritime safety, are developing a ship with a double layer of walls that would give it extra buoyancy, said Claes Kallstrom, a SSPA safety expert.

That would make a ship more resistant to tilting.

"If water was to enter the deck on the new model, it would spread equally over the entire deck to stabilize the ship, instead of weighing down one side," Kallstrom said. "A ship should be able to remain floating up to 24 hours."

Anders Ulfvarson, a maritime technology expert at Chalmers, said blueprints for the new model will be presented within months. A new fleet could be built within a few years, he said.

Such improved safety may not drastically reduce the number of ferry disasters, however, as most take place in poorer countries that often buy used ships from Western nations.

"Those are not sold as dangerous ships, but they become dangerous if they are not maintained," said Anders Ulfvarson, a marine technology expert.

Africa has seen some of the worst ferry disasters in the last decade.

The Senegalese ferry MS Joola capsized Sept. 26, 2002, killing more than 1,800 people. In 1996, a ferry sank in Lake Victoria in east Africa, killing at least 500 people.

Oumar Faye, a retired ferry captain in the Senegalese capital Dakar, says "most companies that operate ferry services care very little about safety standards."

Aside from outdated safety features, Faye blamed overloaded vessels and official corruption for the high rate of sea disasters in Africa. He said inspectors are bribed to ignore defects.

Miles Cowsill, editor of the magazine European Ferry Scene, agreed that inspections are "not as rigorous as they should be" in many parts of the world. "This disaster (in Egypt) sadly doesn't come as a surprise to me," he said.

The Genoa-based Italian Naval Registry said the Al-Salaam Boccaccio 98 passed its last inspection in June 2005.

Spokesman Mario Dogliana warned against premature conclusions that water had entered the ship's car deck. "The ship was always in order, according to the technical norms of international safety," he said.